Title :
Gain and linewidth enhancement factor in InAs quantum-dot laser diodes
Author :
Newell, T.C. ; Bossert, D.J. ; Stintz, A. ; Fuchs, B. ; Malloy, K.J. ; Lester, L.F.
Author_Institution :
Center for High Technol. Mater., New Mexico Univ., Albuquerque, NM, USA
Abstract :
Amplified spontaneous emission measurements are investigated below threshold in InAs quantum-dot lasers emitting at 1.22 μm. The dot layer of the laser was grown in a strained quantum well (QW) on a GaAs substrate. Ground state gain is determined from cavity mode Fabry-Perot modulation. As the injection current increases, the gain rises super-linearly while changes in the index of refraction decrease. Below the onset of gain saturation, the linewidth enhancement factor is as small as 0.1, which is significantly lower than that reported for QW lasers.
Keywords :
III-V semiconductors; indium compounds; laser cavity resonators; optical modulation; quantum well lasers; refractive index; semiconductor quantum dots; spectral line breadth; superradiance; 1.22 mum; GaAs; GaAs substrate; InAs quantum-dot lasers; InAs-GaAs; amplified spontaneous emission; cavity mode Fabry-Perot modulation; dot layer; gain saturation onset; ground state gain; index of refraction; injection current; linewidth enhancement factor; strained quantum well; Charge carrier density; Laser modes; Laser theory; Optical modulation; Optical refraction; Quantum dot lasers; Semiconductor diodes; Semiconductor lasers; Spontaneous emission; Waveguide lasers;
Journal_Title :
Photonics Technology Letters, IEEE
